[guest4091]

David Cooper;

If the emitter/detector E is a fixture of the ring, and thus rotating with the ring, then fig.1 shows E detecting the green light 1st and the blue light 2nd. It's not because light speed has varied, but because the distance traveled in space varied. Green traveled less than 2 pi and blue traveled more than 2 pi.
If a mirror M is located half way at pi and signals sent in opposite directions, as in an equivalent translational motion experiment (fig.2), the signals return simultaneously and verify light speed was c (the 2nd blue line reflecting at x=pi.
What you are measuring is closing speed, green, t=6.28/1.2=5.2 and blue, 6.28/.8=7.85.

Postulate 1. If the circumstance is the same for both, observing a clock moving relative to you, each must observe the same physical behavior, i.e. a slow running clock.
Your problem is still the same as before. Perception is reality confined to the mind. Each has their personal perception of events, BUT, perception does not influence the distant clock. Perception is the processing of images of the distant clock which is passive, looking at the clock does not affect it. That only happens if you are probing microscopic particles with light, as an example. You are confusing observations of an object with the behavior of the object.
light ring e.gif (10.31 kB . 1078x560 - viewed 2117 times)

[David Cooper]

If the emitter/detector E is a fixture of the ring, and thus rotating with the ring, then fig.1 shows E detecting the green light 1st and the blue light 2nd. It's not because light speed has varied, but because the distance traveled in space varied. Green traveled less than 2 pi and blue traveled more than 2 pi.

Of course it isn't because of the speed of the light varying - the speed of light is constant. What is different for the two lots of light is its speed relative to the material it's passing. We have the red light passing through a length of ring in a shorter time than the blue light passes through the same length of ring. The red light is passing through that material at a speed relative to it greater than c, while the blue light is doing so at a speed lower than c.

If a mirror M is located half way at pi and signals sent in opposite directions, as in an equivalent translational motion experiment (fig.2), the signals return simultaneously and verify light speed was c (the 2nd blue line reflecting at x=pi.

Lovely. Why not tell me something else that we agree on.

What you are measuring is closing speed, green, t=6.28/1.2=5.2 and blue, 6.28/.8=7.85.

... which is the speed of the light relative to the material it's passing through.

Postulate 1. If the circumstance is the same for both, observing a clock moving relative to you, each must observe the same physical behavior, i.e. a slow running clock.

The observer co-moving with the emitter/detector (which we can call the e/d) has a single clock which he uses for both measurements. Other observers at rest in other frames can also use a single clock to time the light's journey from the e/d back to the e/d, and they will all measure that the red light moved faster relative to the material it was passing then the blue light did. All honest measurers agree with this.

Your problem is still the same as before. Perception is reality confined to the mind.

I'm not the one with the problem - you are, because all observers see that the red light moves faster relative to the material it passes through (while it's passing through it) than the blue light. [Note that if you average out its speed relative to the material by taking its speed relative to each bit of material throughout the entire trip, you cancel out the effect and hide from yourself the reality of what's happening, but that's the same mistake the Irish made when they built their first train line - they reckoned they could cope fine with a single track because they calculated that the average speed trains passed each other at would be zero, so they thought there was no possibility of them colliding, but they soon learned their mistake and built a second track.]

Each has their personal perception of events, BUT, perception does not influence the distant clock. Perception is the processing of images of the distant clock which is passive, looking at the clock does not affect it. That only happens if you are probing microscopic particles with light, as an example. You are confusing observations of an object with the behavior of the object.

I'm not confusing anything - you're the one failing to grasp what's going on in the thought experiment by imagining that you can play impossible games with observations of clocks. All observers saw the red light leave the e/d at the same moment as the blue light. All observers can see the blue light return to the e/d before the blue light. You appear now to be denying that these observations are valid on the basis that the behaviour of the clocks is not what the observers reading them observe! How can any scientist ever make any measurement then if they aren't allowed to believe the measurements they make? You have just banned all scientists from testing anything by experiment.

[yor_on]

Actually Collin, I don't agree to that. Einsteins relativity theory is about frames of reference. In that theory the only frame that is not relative, is the local one. The one you use to define other frames from, but as your frame of reference is no more 'real' in this context than mine all local frames can be seen as 'relative' too, from a 'global perspective' (aka the 'universe':) If you get my drift. But I still think that here is something very special about locality, and the way 'c' adapt to it.

What I mean is that by defining a 'fixed absolute frame', and proving it, the theory of relativity should be wrong. But that's not possible, at least as unlikely as being able to prove that we live on a turtle. too many experiments, and too many ways to describe how different frames present different physical effects, as in EM

Actually I think that was what Einstein gave his last thirty (?) years to. The way I got it was that he postulated a 'fifth dimension' where those observer dependencies could be explained away, from one 'whole universe' as seen there. He also brought some ideas to it that as I've read still is used in string theory. So maybe you're right after all, he did want a 'absolute frame' to go out from in a way. But that's not the theory of relativity, not as it stands for now at least.

One really need to notice our preconceptions here. Why he wanted the absolute frame is to me equivalent to the way we think that 'my universe is your universe'. The logic of it is 'shared', it has to be to allow a 'co existence', but that's all.

[guest4091]

The observer co-moving with the emitter/detector (which we can call the e/d) has a single clock which he uses for both measurements. Other observers at rest in other frames can also use a single clock to time the light's journey from the e/d back to the e/d, and they will all measure that the red light moved faster relative to the material it was passing then the blue light did. All honest measurers agree with this.

The speed of light is not defined relative to an object. It's defined relative to the vacuum of space (Einstein) or the ether (Lorentz). It is also a constant value and independent of moving matter. You are talking closing speeds.

[David Cooper]

The speed of light is not defined relative to an object. It's defined relative to the vacuum of space (Einstein) or the ether (Lorentz). It is also a constant value and independent of moving matter. You are talking closing speeds.

The term "closing speed" is badly formed as it implies that the two things are approaching each other. It therefore doesn't fit will with other cases of relative speed such as "passing speed" and "separation speed". "Relative speed" is a much better application of language and it's widely understood. Having dealt with the language issue though, what difference does it make to the price of fish? You can translate to "closing speed" in your head every time I say "speed relative to x", and then your mind can convert back to the idea of relative speed when it converts from language to semantic understanding, and then you can apply all that to the thought experiment. A frame of reference asserts that the speed of light relative to objects at rest in that frame (closing/passing/separation speed) is c. Some material has the property that light passing it in some directions is >c reltive to it (so the closing/passing/separation speed is >c). If a frame asserts that the closing/passing/separation speed between light and material with that property is c, then that frame is a misrepresentation of reality. No amount of playing language games will change the fact that the frame is making incorrect assertions and is therefore not a valid frame.

[guest4091]

The speed of light is not defined relative to an object. It's defined relative to the vacuum of space (Einstein) or the ether (Lorentz). It is also a constant value and independent of moving matter. You are talking closing speeds.

The term "closing speed" is badly formed as it implies that the two things are approaching each other. It therefore doesn't fit will with other cases of relative speed such as "passing speed" and "separation speed". "Relative speed" is a much better application of language and it's widely understood. Having dealt with the language issue though, what difference does it make to the price of fish? You can translate to "closing speed" in your head every time I say "speed relative to x", and then your mind can convert back to the idea of relative speed when it converts from language to semantic understanding, and then you can apply all that to the thought experiment. A frame of reference asserts that the speed of light relative to objects at rest in that frame (closing/passing/separation speed) is c. Some material has the property that light passing it in some directions is >c reltive to it (so the closing/passing/separation speed is >c). If a frame asserts that the closing/passing/separation speed between light and material with that property is c, then that frame is a misrepresentation of reality. No amount of playing language games will change the fact that the frame is making incorrect assertions and is therefore not a valid frame.

Relative speed is a good choice, but then, all speeds are relative, since position is relative.
Both versions of Relativity stipulate, measured light speed is constant and independent of it's source. The relative/closing speed varies with the speed of the object, and that doesn't agree with the theory. Example: speed of a water wave is determined by the medium. The speed of a wave relative to a boat would vary with the boat, and is something else. Now I'm just repeating what others have said. When experiments to measure light speed are done, no one gets a value other than c.

The pdf was the math to support SR that observations only depend on relative speed. An absolute frame is redundant.

[David Cooper]

Relative speed is a good choice, but then, all speeds are relative, since position is relative.

Indeed - all speeds are relative to something. The speed of light is c relative to the fabric of space that it travels through (unless it is slowed by obstacles or proximity to mass). The speed of light is also c relative to objects at rest in space. The speed of light is >c in some directions relative to any object that is not at rest in space. The speed of light relative to other light varies between 0 and 2c. If you play magic games with frames of reference though, you can assert that the only speeds of light relative to other light that are allowed are 0, 1.41c or 2c with all values in between being banned, and you are really required to do this if you want to insist that the speed of light relative to all objects is always c. Light moving at any angle other than 0 or 180 degrees to other light can be changed to a 90 degree angle simply by choosing a frame that makes it so, and this is the exact same transformation that you make when you change frame to make an object "at rest" so that the speed of light relative to it is c in all directions. Why would any physicist want to play such an idiotic game with light and light? They wouldn't. But they do play it with light and matter, and they can't see that it's the exact same idiotic game in both cases.

Both versions of Relativity stipulate, measured light speed is constant and independent of it's source. The relative/closing speed varies with the speed of the object, and that doesn't agree with the theory.

That sounds like an attack on SR, so I can't work out what you're trying to say, and your example (below) doesn't clarify things.

Example: speed of a water wave is determined by the medium. The speed of a wave relative to a boat would vary with the boat, and is something else.

The speed of a light wave is determined by the medium (fabric of space). The speed of an object relative to a light wave varies with the speed of the object. Just as the speed of a boat relative to a wave depends on the speeds and directions of travel of boat and wave, the speed of light relative to an object depends on the speeds and directions of travel of the light and the object. The cases are directly equivalent, and the only thing that makes light different from slower-speed waves is that light moves at the fastest possible speed through its medium, leading to an impossibility of measuring its actual speed relative to any object because of the phenomenon of relativity (Lorentz's) which explains in full why the true speed is always masked.

Now I'm just repeating what others have said. When experiments to measure light speed are done, no one gets a value other than c.

And that isn't in dispute. Lorentz's relativity tells you to expect that, so no amount of repeating it will add any relevance to the case in question. We have a thought experiment (backed by actual experiments) which shows that some light must pass some objects at >c relative to them, which means that any frame of reference that asserts that the speed of light relative to such objects is c in all directions is necessarily a misrepresentation of reality, and the existence of such invalid frames disproves SR.

The pdf was the math to support SR that observations only depend on relative speed. An absolute frame is redundant.

An absolute frame is not only mechanistically essential, but it is shown to exist by my thought experiment through the disqualification of all other frames on the basis that they misrepresent reality by asserting that objects don't have a property which they must have.

[David Cooper]

The involvement of "Dressed_Scientist" in this discussion reminds me once more of Hans Christian Andersen's wonderful story, The Emperor's New Clothes. I've always liked the story, even though one aspect of it seemed highly implausible - that no one else dared to point out that the Emperor was naked before the little boy spoke up (although it was just a story and it's perfectly forgiveable if it doesn't map precisely to reality). I realise now though that I was quite wrong about which part of the story was unrealistic. In the real world, people are indeed scared to speak out if they think they'll look stupid by doing so by going against authority. It turns out that it's the ending of the story that's unrealistic, because when the little boy shouted that the king had nothing on, everyone ought to have turned to him and called him an idiot, and having done so, they'd have gone off to buy some special clothes from the same merchant, populating the street with more and more naked people who have fallen for the same scam, all the way until the boy is the only person left wearing clothes.

Why do people remain fixed in positions that have been shown through mathematical proof to be wrong? The red light passes all the material of the ring in a shorter time than the blue light does. The red light travels relative to some of that material at >c relative to it. Some material exists in our universe which has the property some of the time that some light travels past at >c relative to it. Any frame of reference that asserts that such material doesn't have that property when it does have that property is misrepresenting reality. As soon as one frame is shown to be doing this, Einstein's original SR model is disproved, at which point we should turn to exploring the other SR models (which have also been disproved by other means). What happens in these threads? There's a mathematical proof sitting there which no one can shoot down because it's correct, but they don't have the courage to admit it. Instead, they just go back to where they were in the next thread and parrot the old assertions about there being no absolute frame as if nothing has happened.

[guest4091]

David Cooper;

A frame of reference asserts that the speed of light relative to objects at rest in that frame (closing/passing/separation speed) is c.

---
Frames don't make assertions!
The theory (SR or LET) states, 'The propagation speed of light in space, as measured in an inertial frame is a constant c, and independent of it's source'. That implies the light does not acquire the speed of the emitter. If the observer A in that frame concludes light speed should be c-v, since he is moving in the same direction at v (relative to the frame he left), a measurement will prove him wrong. If a 2nd observer B watches A and the light signal pass him, he will measure A moving at w and the light moving at c. He will also calculate the gap between A and the signal as increasing at c-w, but that fact is irrelevant, since the A and B measurements are independent of each other. If A and the signal moved in opposite directions, the gap speed would be c+w, and still be irrelevant, since the gap is not a material object. The gap has no direction of motion, thus it is not a velocity. There is nothing (no thing) violating postulate 2.
If c is constant and independent, it can't vary as c±v. That is definitely a contradiction so fundamental, there is no excuse for anyone, in any field, to not be able to comprehend it.
The moving observer cannot detect his own speed because it varies depending on the  reference, thus cannot measure c±v.
---

Some material has the property that light passing it in some directions is >c reltive to it (so the closing/passing/separation speed is >c).
If a frame asserts that the closing/passing/separation speed between light and material with that property is c, then that frame is a misrepresentation of reality.

---
The only property of materials that affects light speed is the 'index of refraction'.
Light takes more time to traverse 1 cm of glass than 1 cm of air.

You claim to have had an unpleasant experience in the early education system. Why should that lead to an attack on established scientific theories?

[David Cooper]

Frames don't make assertions!

Of course they do - whenever you pick a frame of reference to make an object "at rest" and the speed of light relative to it c in all directions, that frame necessarily asserts that the speed of light relative to itself (the frame), and by extension to any object at rest relative to itself (again the frame), is c.

The theory (SR or LET) states, 'The propagation speed of light in space, as measured in an inertial frame is a constant c, and independent of it's source'. That implies the light does not acquire the speed of the emitter.

Obviously. The frame dictates that the light moves relative to it (the frame) at c.

If the observer A in that frame concludes light speed should be c-v, since he is moving in the same direction at v (relative to the frame he left), a measurement will prove him wrong.

No measurement can prove him wrong - all he can do is measure the apparent speed of light relative to him, and that will come out as c even if the real speed of that light relative to him is c-v.

If a 2nd observer B watches A and the light signal pass him, he will measure A moving at w and the light moving at c. He will also calculate the gap between A and the signal as increasing at c-w, but that fact is irrelevant, since the A and B measurements are independent of each other. If A and the signal moved in opposite directions, the gap speed would be c+w, and still be irrelevant, since the gap is not a material object. The gap has no direction of motion, thus it is not a velocity. There is nothing (no thing) violating postulate 2.

Neither A nor B is capable of measuring the speed of light relative to anything other than the fabric of space, so that's all they are doing - they are not measuring the speed of light relative to themselves unless they happen to be at rest in space, so if they make any claim that the speed they're measuring is the speed of light relative to themselves, they are incompetent.

If c is constant and independent, it can't vary as c±v. That is definitely a contradiction so fundamental, there is no excuse for anyone, in any field, to not be able to comprehend it.

The speed of light does not vary at all relative to space (unless it is slowed by other material or the influence of gravity). Anyone who doesn't comprehend that is indeed incompetent, as is anyone who suggests that other people are failing to comprehend something that they fully comprehend and which they consistently apply in all their statements.

The moving observer cannot detect his own speed because it varies depending on the  reference, thus cannot measure c±v.

Correct.

Some material has the property that light passing it in some directions is >c reltive to it (so the closing/passing/separation speed is >c).
If a frame asserts that the closing/passing/separation speed between light and material with that property is c, then that frame is a misrepresentation of reality.

---
The only property of materials that affects light speed is the 'index of refraction'.
Light takes more time to traverse 1 cm of glass than 1 cm of air.

You are wilfully misunderstanding mathematical language in an attempt to ban me from describing an attribute of something as a property, and you could doubtless play the same language game with the word "attribute", but what you're actually doing is playing games with words instead of going on honest interpretation. The argument doesn't depend on the words "property" or "attribute" - I was simply using them as grammatical tools to link parts of different sentences to each other (to reduce the risk of referential failure), but the same job can be carried out by using the word "that":-

Light is passing some (or all) of the material of the ring at >c relative to it. Some of that material has light passing it in some directions at >c. A frame of reference that represents that material as being at rest is asserting that the speed of light relative to that material is c in all directions.

You claim to have had an unpleasant experience in the early education system. Why should that lead to an attack on established scientific theories?

What the heck is that? What kind of game are you trying to play now? I found school to be a waste of time because they spent the first seven years of it teaching me practically nothing - they stole a massive chunk of my childhood (which I could have made much better use of if I hadn't been stuck in what was little more than a prison) and gave me nothing in return. But why in the world would I turn that into a grudge against Einstein or anything else in science?  Science and Einstein weren't to blame. You're attempting to play the man instead of the ball, but you're not going to get very far with that as I have no vices. I could bring up some of Einstein's failings, but I have no wish to describe them as they have nothing whatsoever to do with his theories - to resort to such tactics is a game for the losers of arguments rather than winners.

Your job is either to find a fault in the proof or to agree that it is correct, and you should be able to do one or the other in a very short time. If you are incapable of determining whether it is correct or incorrect, you are not sufficiently competent to make any assertions about the validity of SR (and the same applies to anyone else).

The theory and the proof that it's wrong are independent of the personalities involved, so they must be examined impartially on their own merits, and no amount of authority should be used to guide any judgements - they should stand or fall entirely by their own logic (and by how well they fit the facts of measurement). Remember too what Feynman said about theories: it doesn't matter how beautiful they are - if they don't fit the facts of experiments, they're wrong. Here we have have a theory which cannot account for the crucial difference between frames which misrepresent reality and frames which don't misrepresent it, and we also have a proof (backed by experiments) that some frames are misrepresenting reality. By Feynman's test, SR is dead.

So, if you think it's wrong, where does the proof break down?

Q1: Does the red light pass all the material of the ring in a shorter time than the blue light does?

Yes. To disagree with this is to go against the measurements of experiments like MGP and Sagnac.

Q2: Does the red light travel relative to some of that material at >c.

Yes. To disagree with this is to reject the measurements of actual experiments.

Q3: Does some material exist in our universe which has some light travelling past at >c relative to it in some directions?

Yes. To disagree with this is to reject the measurements of actual experiments.

Q4: Is a frame of reference that asserts that such material doesn't have light travelling past at >c relative to it misrepresenting reality?

Yes. To deny this is to fail to understand what frames of reference are.

Q5: Do frames exist that misrepresent reality in this way?

Yes. No other answer is rational if you answered "Yes" to the previous questions.

Q6: Does SR allow some frames to be less valid than others?

No. SR doesn't accept that there is any difference between frames which correctly represent reality and frames which misrepresent reality. SR is therefore incompetent as a model [while we're dealing with SR models where the speed of light is c as opposed to being zero or infinite as in Minkowski Spacetime versions - those other versions of SR can be disproved in other ways, although one can be "salvaged" by introducing Newtonian time into it in order to allow it to tolerate event-meshing failures and hide them over the course of Newtonian time].

Q7: Is it possible to extend the argument to show that only one frame can be a true representation of reality while all others are misrepresentations?

Yes, but there is no need to go that far to disprove SR as that job was done as soon as it was shown that there must exist at least one frame that misrepresents reality.

[guest4091]

David Cooper;

In the rotating ring experiment, E is the emitter/detector, t=d/c with d the circumference of the ring.
The red light moves opposite to the rotation and meets E at time<t.
The blue light moves with the rotation and overtakes E at time>t.
An observer in the ref. frame of the ring center knows the rotation affects the light transit time, and explains the difference in detection of the red and blue light. The space between red light and the detector is closing at c+v and the space between blue light and the detector is closing at c-v. 
There is nothing moving at c±v.
The same experiment with opposite rotation would result in blue earlier and red later. This supports rotation as producing the results, not a change in light speed.
In a test for light speed over a measured distance, identical rods extending in opposite directions, the timing woud be equal, just as with inertial motion.

[David Cooper]

An observer in the ref. frame of the ring center knows the rotation affects the light transit time, and explains the difference in detection of the red and blue light.

Indeed it does.

The space between red light and the detector is closing at c+v and the space between blue light and the detector is closing at c-v.
There is nothing moving at c±v.

The light is moving at c at all times. E may be speeding up and slowing down as it goes round, but it could also be moving at a constant speed - different frames of reference make up different stories about what it's doing. All frames of reference agree on one point though, and that is that the red light passes through the material of the cable at >c relative to it (while passing through it), while the blue light passes through that same material at <c relative to it. No amount of ignoring that fact (and fixating on other issues as a diversion) will make it go away.

The material of the ring has a length, and that length is the same in both directions round the ring. The two lots of light travel at different speeds relative to that material.  (This should be measured sector by sector with the ring divided up into lots of sectors because we don't want to hide the effect from ourselves by taking the speed of the light relative to each point for the full journey of the light - we are interested in the relative speed of the light to each atom that it passes at the point of nearest approach.) If you do this maths in a competent manner, as a real scientist should, you must determine that the red light passed the material of the ring at an average relative speed >c. This guarantees that the red light passes some of that material at a relative speed >c. Some material therefore exists which some of the time has light pass it at >c relative to it. Any frame of reference which asserts that light passes such material at c relative to it in all directions at a time when light is actually passing it at >c relative to it is therefore misrepresenting reality. Some frames do exactly that, so some frames are not valid. SR doesn't allow them not to be valid. SR therefore fails to match up to the real universe.

The same experiment with opposite rotation would result in blue earlier and red later. This supports rotation as producing the results, not a change in light speed.

No one is claiming there's a change in light speed.

In a test for light speed over a measured distance, identical rods extending in opposite directions, the timing woud be equal, just as with inertial motion.

In the case of a straight line course, what you do is synchronise clocks on the basis that the course is at rest and then use those timings to measure the apparent speed of light. If you then accelerate the course so that it's no longer at rest in the original frame, you use a different synchronisation and declare it to be at rest in a new frame, then you make measurements as before and again get the apparent speed of light from them. What you have done is change your assertion of the speed of light relative to an observer who is at rest in the first frame throughout. The frame asserts that light passed that observer at c relative to him in all directions. The new frame asserts that light passes him at >c relative to him in some directions. You simply change frame as it suits you to put things at rest in a frame so that you can always claim that the speed of light is c in all directions relative to those things, and you completely ignore the fact that every other frame disagrees with that assertion. You have been programmed to ignore the infinite number of contradictions that this silly theory generates. You have been taken in by this voodoo because someone can always show you a frame which makes the speed of light c relative to any object c in all directions relative to it and then appeal to authority to make you conform. However, we now have this case where the speed of light relative to the material of the ring is on average >c as measured from ALL frames, so you can't switch to any frame that hides the truth from you and sweep all the contradictions under the carpet (the assertions of relative speeds >c which all other frames are making). It this case, all frames make the same assertion and there is nowhere for you to hide from the reality of it: the truth is that light must be passing some material at >c, and no amount of playing frame-shifting games can brush that under the carpet. The reality is starkly exposed: that some frames misrepresent reality.

[guest4091]

The reality is starkly exposed: that some frames misrepresent reality.

From the LT, t’= γt, and x’= γx, with t and x coordinates in U, the abs. rest frame.
The combined effect of time dilation and length contraction results in the A frame being scaled by 1/γ relative to the U frame. Since any inertial frame is equivalent to a scaled U frame, with (γx/γt) = x/t, all inertial frames inherit the same relations expressed in terms of space (x) and time (t). Therefore any inertial frame may serve as a reference frame. The first postulate of SR is now a consequence of the second.

Any observer in any inertial frame may use the same expression, x/t=v to calulate speed. If v=c in the U frame, then v will =c in all inertial frames. That is the proof to support the 2nd postulate. If you don’t understand this, the problem is not with SR, but with your interpretations.

[David Cooper]

From the LT, t’= γt, and x’= γx, with t and x coordinates in U, the abs. rest frame.
The combined effect of time dilation and length contraction results in the A frame being scaled by 1/γ relative to the U frame. Since any inertial frame is equivalent to a scaled U frame, with (γx/γt) = x/t, all inertial frames inherit the same relations expressed in terms of space (x) and time (t). Therefore any inertial frame may serve as a reference frame. The first postulate of SR is now a consequence of the second.

Of course any inertial frame may serve as a reference frame, but only one such frame (at most) can represent reality correctly (at any location). Any change of frame is a change in the asserted speed of light in some directions relative to an object: you are switching from one frame to a different one which produces an incompatible account of the speed relationships between things (including light), and to claim that both are true representations of reality is an illegal mathematical move. This is secretly recognised by the people at the top in the SR camp who already know that it is irrational, which is why they switch over to a Minkowski Spacetime model where light has no speed because it reduces all paths for light to zero length (which again they don't like to state openly because it sounds so ridiculous), although they still try to have their cake and eat it - the only way they can maintain this idiocy is by using three different incompatible disproved SR models and pretending they are all the same model in order to provide the illusion that they work, but when you interrogate them by simulating them in a computer, they all fail to function as claimed and need to be patched by bringing in things that are external to the model (and in each case specifically banned from it).

Any observer in any inertial frame may use the same expression, x/t=v to calulate speed. If v=c in the U frame, then v will =c in all inertial frames. That is the proof to support the 2nd postulate. If you don’t understand this, the problem is not with SR, but with your interpretations.

You appear to be incapable of understanding the issue (although it may be deliberate avoidance as you continue to bury your head deeper and deeper in the sand). No amount of calculating the apparent speed of light relative to you to be c will make the actual speed of light c relative to you, and no amount of switching frame and recalculating using maths that's guaranteed to go on throwing the same value c at you every time will make the actual speed of light relative to everything c. My thought experiment proves that the speed of light relative to some things is >c, but you're unwilling to accept that purely because it goes against an irrational belief which you have carelessly allowed to take over your mind. You studiously ignore the facts, just like religious people do when their beliefs are questioned. Look at what your beliefs have done to you - you are incapable of agreeing that the speed of light relative to some material in the ring must be >c, even though anyone with any competence with maths can see that this has to be the case. Why are you rejecting facts? Why are you backing belief over facts? If Galileo showed someone the moons of Jupiter through his telescope and that religious person told him they aren't there and that he's making it all up, what would you think of that person who acts as a mindless tool of an irrational belief system which is rooted solely in authority? Why do you just trust the people who told you that SR is right instead of interrogating it properly to see if it really works? The most shocking thing here is that you can't bring yourself to agree that the speed of light relative to some material in the ring must be >c even though we have two lots of light passing through it in opposite directions at c with one lot completing the trip in less time than the other lot. What do you do instead? Ignore the evidence. Divert attention away from the evidence. Accuse me of attacking SR out of a grudge! Tell me I don't understand something irrelevant that I fully understand. State irrelevant things about c which LET fully agrees with. You squirm about all over the place instead of committing yourself to direct answers to the key questions. Why is something that's supposed to be scientific being defended through such unacceptable tactics instead of through honest examination of facts? (And it's not just here - the same irrational defenders of the faith are in evidence on every science forum on the Net, all making the same illegal moves while studiously ignoring the facts that are placed before them.) On this issue (relativity), you're not doing science; but religion.

[alancalverd]

A thought experiment cannot prove anything. It can only produce more or less logical deductions from its initial premises. Navigating around the world with a ring laser gyroscope suggests that relativity is correct.

[guest4091]

DC;

My thought experiment proves that the speed of light relative to some things is >c,

A moves left at .6c and B moves right at .6c.
My thought experiment proves that the speed of A relative to B is >c.
So what?

[David Cooper]

A thought experiment cannot prove anything. It can only produce more or less logical deductions from its initial premises. Navigating around the world with a ring laser gyroscope suggests that relativity is correct.

My thought experiment has inadvertently been done for real though: experiments like MGP and Sagnac prove that it would work exactly the way I've described. This means that SR has been tested and found to fail to match up to reality because it claims there is no difference between frames which misrepresent reality and frames which don't.

[David Cooper]

DC;

My thought experiment proves that the speed of light relative to some things is >c,

A moves left at .6c and B moves right at .6c.
My thought experiment proves that the speed of A relative to B is >c.
So what?

You can switch to a frame where the asserted relative speed between them is <c and then play your usual game where that is more important than the claim of the first frame used for the measurements which contradict it. The key thing with my thought experiment (which has been done for real) is that there is no frame which you can switch to to eliminate the measurements showing light moving at >c relative to some of the material of the ring as it passes it. This means that some material certainly exists which has light pass it in some directions at >c relative to it rather than at c, and as soon as we know that such material must exist, we also know that any frame which represents that material as having light pass it at c relative to it in all directions is misrepresenting reality. You have had this explained to you dozens of times now, and yet you refuse to take it on board.

[alancalverd]

This means that SR has been tested and found to fail to match up to reality because it claims there is no difference between frames which misrepresent reality and frames which don't.

Do you write Donald Trump's speeches? "According to Special Relativity, all lies are equivalent to the truth", eh? Genius.

[guest4091]

You have had this explained to you dozens of times now, and yet you refuse to take it on board.

Look in the mirror.
And the rotating frame is absolute motion, since all parts are moving at different speeds and there can be no reciprocal frame. You don't recognize proof when you see it!
Your assessment of my abilities makes me wonder if I can still make toast in the morning.